1. Field of the Invention
Present embodiments relate generally to a closure or a pressure vessel or pipe. More specifically present embodiments relate to a closure mechanism for locking or unlocking a closure for a pressure vessel or pipe system.
2. Description of the Related Art
Closures for pressure vessels and pipes typically utilize a round door or head adapted to fit in the aperture of a body or hub. The hub is connected to a vessel or pipe system or other structure which is typically pressurized. The door or head is lockingly engaged to the hub when in the closed position so that the system or vessel may be pressurized without unknowingly allowing for opening of the head from the hub.
A bore or aperture of the hub has an inner circumferential groove for supporting a portion of a locking member. The door has a locking ring proximate a circumferential portion of an outer surface of the door wherein the locking ring is engaged to cooperate with the groove about the aperture after the door is closed and seated in the aperture. These locking members are typically biased by a band or ring which is caused to expand or contract, causing the same expansion or contraction of the locking ring to lock or unlock the door from the hub.
One problem with known closure structures is being able to apply enough force to an opening handle or other linkage structure to open or release a locking ring which engages the head with the circumferential groove of the hub.
It would be desirable to have a system which utilizes a known minimal range of motion for a handle to which a suitable amount of force may be applied comfortably by the user in order to release a locking ring while still providing a safe system which will not disengage inadvertently while the system is pressurized.